jaaade​, I also use the mass text massaging feature on my phone and understand how important it is for you to have this feature to working properly. When creating the massage by selecting your contacts and then tapping on "Just Me", you will then have a chance to input the massage you want to send.  After the message is sent, it will all compile into one text message screen for you, however it will state "Group Mode set to: Mass Text".  Are you seeing this message after "Just Me" texts are being sent? Are you receiving their replies within the complied text message screen or individually?

Here to help,

yarelim_vzw​